When driving cylinders or groups of cylinders by the use of separate drives, such as, for example, in satellite printing units, process-related unwinding differences between the cylinder pairs can occur. These differences are a function of the contact pressure, the number of active print locations, the thickness of the dressing, the type of dressing, and even the manufacturer of the dressing itself. This is true whether the friction drive is embodied without bearing rings or with bearing rings, or of the bearing rings or of the radius ratios of the friction drive as a whole.
In part, these process-related unwinding differences can lead to considerable and, under changing conditions to different output flows between the cylinders or cylinder groups. This is undesirable, since such differences lead to asymmetries in the output configuration or, depending on the conditions and modes of operation, to different outputs, or even to overloading of the motors and regulating devices.
Even with cylinder groups, printing groups, printing units or printing towers which are operated together by the use of gears, this difference leads to undesired moments, to increased friction and to wear.
Cylinders of a rotary printing press, with bearing rings, are known from DE 195 01 243 A1. The bearing rings of the satellite cylinder are rotatably seated for the purpose of reducing the output transfer.
In WO 00/41887 A1, a compensating friction gear, in the form of bearing rings having a radius ratio not equal to one, is overlaid on a friction gear of cylinders which are in frictional contact for process-related reasons. In this case, the bearing ring of the counter-pressure cylinder is larger than the barrel of the latter and is also larger than the bearing ring of the cooperating transfer cylinder. In the priority document DE 199 27 555 A1, the relationships between the transfer cylinder and the counter-pressure cylinder are shown, in the reversed way, in a drawing figure.
U.S. Pat. No. 3,196,788 discloses a printing group for use in offset printing on two sides. The transfer cylinders and the associated forme cylinder have different radii in the area of their barrels. Three pairs of bearing rings, which are each working together, are arranged on three different levels. Each of the pairs of bearing rings has the same diameter.
In U.S. Pat. No. 2,036,835 A, the ratios of the diameters of the cylinders with respect to each other, are shown in such a way that the transfer cylinder diameter is smaller, and the counter-pressure cylinder and forme cylinder diameters are larger than the diameters of the bearing rings. The bearing ring diameter is identical for all three cylinders.